THE PLANKTON DIATOMS OF THE 

 SOUTHERN SEAS 



By N. Ingram Hendey, f.l.s., f.r.m.s. 

 (Text-figs. 1-3; Plates VI-XIII) 



INTRODUCTION 



The amount of phytoplankton material obtained during the Discovery Committee's 

 investigations is so enormous that it was decided that a complete analysis of all the 

 available material, apart from being an almost unsurmountable task, would serve no 

 useful purpose in compiling a systematic account of the species of diatoms. A survey of 

 all the material in hand at the time of writing was therefore made, and lines of stations 

 from many different and widely spread areas were selected in order to provide as com- 

 plete a picture as possible of the diatom population south of the Equator. Although the 

 majority of the material was obtained from the Southern Ocean between 50 and 65 S, 

 and 10 and 70 W, and particularly from the neighbourhood of South Georgia, many 

 lines of stations were made in other parts that yielded a wealth of material quite un- 

 surpassed heretofore. 



The material selected for this work comes from many stations around South Georgia, 

 the South Sandwich Islands, the South Shetlands, and the Bransfield Strait. Several 

 stations in the Weddell Sea and the Bellingshausen Sea provided information con- 

 cerning those diatoms which live under truly Antarctic conditions. A line of stations 

 from the Falkland Islands to the mainland, together with several stations off the Brazil 

 coast, provided information concerning the diatom flora of the south-western Atlantic. 

 Other Atlantic material was obtained from a line of stations along the 30th W meridian 

 from the east of the Sandwich Group to the Cape Verde Islands, and several stations off 

 the west coast of Africa. Numerous lines of stations radiating from South Africa were 

 selected, and a number of isolated stations much farther south, between the Cape and 

 Enderby Land. Facts concerning the diatom flora of the Indian Ocean, particularly the 

 neritic species, were obtained from nets taken on a line of stations along the east coast 

 of Africa from the Cape almost to Aden, made upon the homeward journey of the 

 ' Discovery II ' during the 1933-5 commission. The diatom flora supported by the Peru 

 Current off the west coast of South America was sampled during the work of the 

 'William Scoresby' in 1931, and material obtained from a line of over forty stations 

 from the Straits of Magellan to the Equator was examined. This material was very rich 

 in neritic forms. Two other sources of material may be mentioned, although their yield 

 was very small, the first being the diatoms obtained from melted ice taken in the 

 Bellingshausen Sea, the second consisting of those found in the skin film of certain 

 species of whales. 



The great advantage of examining material from such a variety of localities is that one 

 is able to study the diatom population in its broader aspects and in so doing to avoid 



